Born in County Waterford, St. Ita later settled in County Limerick, at a place that came to be known as Killeedy, or "church of Ita." In addition to founding a community of nuns there, she also seems to have run a school for boys, who were taught faith in God, simplicity of life, and generosity with love. St. Brendan the Voyager was just one of several Irish saints who were her pupils.

St. Ita was known especially for her rigorous fasting and austere personal habits. According to one story, when a rich man pressed a gold piece into her hand, she immediately sent for water to wash her hand. She is said to have written an Irish lullaby, which she sang to the baby Jesus when he appeared to her.